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Home >> Chevrolet >> 2000 >> Metro Base, 2D Hatchback >> Repair and Diagnosis >> Engine Mechanical >> Cooling Fan >> Engine Cooling Fan System - Troubleshooting >> Electric Cooling Fan Circuit Diagnosis >> 3.1L "W" Body (Lumina) >> Procedure No. 2

Procedure No. 2

  1. If cooling fan functional check has been performed, go to next step. If cooling fan functional check has not been performed, see COOLING FAN FUNCTIONAL CHECK .
  2. If either fan turned on when low speed fans was commanded on, go to next step. If neither fan turned on when low speed fans was commanded on, go to step  5.
  3. Using scan tool, command high speed fans on. If inoperative fan from previous step turned on, go to next step. If inoperative fan from previous step did not turn on, go to step  20.
  4. Disconnect fan control relay 3. If inoperative fan from step 2 turned off, go to step  23. If inoperative fan from step 2 did not turn off, go to step  22.
  5. Disconnect fan control relay 1. Using scan tool, command low speed fans on. Probe low speed fans control circuit (Dark Green wire) at fan control relay 1 connector using test light connected to battery voltage. If test light illuminates, go to next step. If test light does not illuminate, g to step  13.
  6. Probe both feed circuits (Orange wire and Red wire) at fan control relay 1 connector using test light connected to ground. If test light illuminates for both circuits, go to next step. If test light does not illuminate for both circuits, go to step  24.
    7. NOTE: Leave fused jumper in place for remainder of this procedure.
  7. Connect fused jumper (30-amp) between switch feed circuit (Red wire) and engine coolant fan motor 1 feed circuit (Light Blue wire) at fan control relay 1 connector. If both fans turn on, go to step  25. If both fans do not turn on, go to next step.
  8. Disconnect engine coolant fan motor 1. Probe engine coolant fan motor 1 feed circuit (Light Blue wire) at fan harness connector using test light connected to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step  27.
  9. Connect second fused jumper (30-amp) between engine coolant fan motor 1 harness connector terminals. If engine coolant fan motor 2 turns on, go to step  17. If engine coolant fan motor 2 does not turn on, go to next step.
  10. Reconnect engine coolant fan motor 1. Disconnect fan control relay 2. Probe switch feed circuit (Black wire) at fan control relay 2 connector using test light connected to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step  28.
  11. Using second fused jumper, connect fused jumper between switch feed circuit (Black wire) and engine coolant fan motor 2 feed circuit (White wire) at fan control relay 2 connector. If both fans turn on, go to step  29. If both fans do not turn on, go to next step.
  12. Reconnect fan control relay 2. Disconnect engine coolant fan motor 2. Probe engine coolant fan motor 2 feed circuit (White wire) at fan harness connector terminal using test light connected to ground. If test light illuminates, go to step  16. If test light does not illuminate, go to step  19.
  13. Ensure test light is still connected. Turn ignition off. Disconnect PCM. Probe low speed fans control circuit (Dark Green wire) at PCM connector using fused jumper (15 amp) connected to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step  15.
  14. Check PCM connector for poor connections. Check engine wiring harness junction block 1 for open or poor connections. If problem was found, repair as necessary. After repairs, perform COOLING FAN FUNCTIONAL CHECK . If problem was not found, go to step  31.
  15. Repair open or short to voltage in low speed fans control circuit. After repairs, perform COOLING FAN FUNCTIONAL CHECK .
  16. Check fan motor ground circuit (Black wire) for open or poor connections. If problem was found, repair as necessary. After repairs, perform COOLING FAN FUNCTIONAL CHECK . If problem was not found, go to next step.
  17. Check fan motor connector for poor connections. If problem was found, repair as necessary. After repairs, perform COOLING FAN FUNCTIONAL CHECK . If problem was not found, go to next step.
  18. Replace fan motor. After repairs, perform COOLING FAN FUNCTIONAL CHECK .
  19. Repair open in engine coolant fan motor 2 feed circuit (White wire). After repairs, perform COOLING FAN FUNCTIONAL CHECK .
    20. NOTE: If fuse is open, locate and repair short to ground on load circuit or shorted component.
  20. Check supply circuit to inoperative fan for open or short to ground. If problem was found, repair as necessary. Replace fuse. After repairs, perform COOLING FAN FUNCTIONAL CHECK . If problem was not found, replace fuse. Then go to next step.
  21. Replace fan which was not operating. After repairs, perform COOLING FAN FUNCTIONAL CHECK .
  22. Replace fan control relay 3. After repairs, perform COOLING FAN FUNCTIONAL CHECK .
  23. Check the following circuits/components for short:
    • Fan control relay 2 switch feed circuit (Black wire).
    • Engine coolant fan motor 2 feed circuit (White wire).
    • Engine coolant fan motor 2.
    • Engine wiring harness junction block 1.

    If problem was found, repair as necessary. After repairs, perform COOLING FAN FUNCTIONAL CHECK . If problem was not found, go to step  29.

    24. NOTE: If fuse is open, locate and repair short to ground on load circuit or shorted component.
  24. Repair open or grounded circuit for circuit that did not illuminate test light. After repairs, perform COOLING FAN FUNCTIONAL CHECK .
  25. Check fan control relay 1 connector for poor connections. If problem was found, repair as necessary. After repairs, perform COOLING FAN FUNCTIONAL CHECK . If problem was not found, go to next step.
  26. Replace fan control relay 1. After repairs, perform COOLING FAN FUNCTIONAL CHECK .
  27. Repair open in engine coolant fan motor 1 feed circuit (Light Blue wire). After repairs, perform COOLING FAN FUNCTIONAL CHECK .
  28. Repair open in fan control relay 2 switch feed circuit (Black wire). After repairs, perform COOLING FAN FUNCTIONAL CHECK .
  29. Check fan control relay 2 connector for poor connections. If problem was found, repair as necessary. After repairs, perform COOLING FAN FUNCTIONAL CHECK . If problem was not found, go to next step.
  30. Replace fan control relay 2. After repairs, perform COOLING FAN FUNCTIONAL CHECK .
  31. Replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. After repairs, perform COOLING FAN FUNCTIONAL CHECK .
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